You mean there are extra BG2 classes in addition to Neverwinter Night 2 ones? Uh-oh. But you still can pick a female wood elven monk with 20 strength from the begnning, right?
I'm pretty sure Pain Elemental is referring to the inclusion of Kaedrin's Prestige Class Pack. That mod adds a dizzying number of prestige classes and a few base classes to boot. To my knowledge there are no Baldur's Gate specific classes, especially since the added classes in BG2 were taken from D&D 3.0 in the first place.
Still, there is a lot of content to process. I ended up making a Warlock.